Project - Geology
Casino Geology Map
Casino Geology Section Diagram
Casino is mainly a copper and gold deposit and typical of many porphyry copper deposits. The deposit, which ranks among the largest in the world, is centered on the 70-million-year-old, Patton Porphyry, which intrudes older, surrounding rocks from the Dawson Range Batholith and Yukon Crystalline Complex. The intrusion caused brecciation (break-up, fragmentation) of both the Patton Porphyry and surrounding rocks mainly along their northern, southern and eastern contacts, resulting in contact breccias (rocks made of rock fragments cemented by a fine-grained matrix). This intrusive complex, covering an area of about two square kilometres, is the Casino deposit.
The most prevalent mineralization is copper, gold and molybdenum, which was deposited from hydrothermal fluids (hot, mineral-rich solutions) mainly in fractures within the contact breccias and fractured wall rocks. Better metal grades occur in the breccias and gradually decrease outwards away from the contact zone both towards the centre of the Patton Porphyry and outward into the older, surrounding rocks.
For more information about the project’s geology, please view the Feasibility Study.
Casino Deposit Mineralization:
Leached Cap Mineralization (CAP)
- This oxide gold zone is gold-enriched and copper-depleted due to supergene alteration processes.
- These near-surface processes enrich the deposit by natural fluids (rain and snow melt) moving and redistributing copper ore minerals downward through the rocks. The enrichment of gold in this zone occurs due to the lower specific gravity of this zone relative to the other supergene zones. Copper (sulphide) minerals were oxidized and leached (dissolved) and moved downward, and weathering replaced most minerals with clay. The weathering is most intense at the surface and decreases with depth.
Supergene Oxide Mineralization (SOX)
- This zone is copper-enriched, with trace amounts of molybdenite.
- This zone is not well formed and generally irregular in shape and distribution. It generally occurs as a thin layer above the supergene sulphide zone (SUS). Where present, the supergene oxide zone averages 10 m thick, and can contain oxide copper minerals (minerals with hydrogen, oxygen and carbon in the chemical composition rather than sulphur), such as chalcanthite, malachite and brocanthite, with minor azurite, tenorite, cuprite and neotocite.
Supergene Sulphide Mineralization (SUS)
- Supergene copper mineralization occurs in a weathered zone below the leached cap, in the supergene oxide zone, and above the hypogene zone.
- The top of the zone is 30 to 70 m below the surface and it has an average thickness of 60 m. Grades of the Supergene sulphide zone vary widely (but are highest in zones that are fractured and contain large amounts of pyrite) due to their ability to promote leaching and precipitation of chalcocite (an important copper ore mineral). The copper grades in the Supergene Sulphide zone are almost double the copper grades in the Hypogene (0.43% copper versus 0.23% copper).
- Hypogene mineralization occurs throughout the various alteration zones of the Casino deposit, as mineralized stockwork veins and breccias. Hopogene refers to primary ore minerals formed deep below the surface from rising fluids.
- Significant copper-molybdenite mineralization is related to the potassic-rich (potassium feldspar) altered breccia surrounding the core Patton Porphyry, as well as in the adjacent phyllic-rich (sericite-pyrite-quartz) altered host rocks of the Dawson Range Batholith. The pyrite halo in this mineralization is host to the highest copper values on the property.
Product – Fact Sheet